Most of existing hybrid automobiles have a configuration in which a big, box-shaped case for an inverter is fixed to a chassis, under which a motor case (trans axle) is arranged. Considering a drive device of a hybrid vehicle that can be mounted on as many vehicle types as possible, the configuration with two cases makes it difficult to share components, since their arrangement is to be optimized for each vehicle type.
Essentially, it is desirable to store and integrate units required to be combined for operation, in one case. Japanese Patent Laying-Open No. 2004-343845 and Japanese Patent Laying-Open No. 2001-119961 disclose a drive device of a hybrid vehicle in which a motor and an inverter are integrated.
However, the drive device of a hybrid vehicle disclosed in Japanese Patent Laying-Open No. 2004-343845 and Japanese Patent Laying-Open No. 2001-119961 has such a structure in that an inverter is merely placed on a motor, and there is room for improvement in the position of center of gravity of the vehicle as for the height direction when the drive device is mounted on the vehicle. Moreover, no consideration is given to space saving in the space where the drive device of a hybrid vehicle is mounted.
In order to enable mounting on many vehicle types, it is desired that an inverter and a motor can be arranged in an outline approximately equivalent to that of an automatic transmission arranged adjacent to an engine in a usual vehicle.
As discussed above, in a drive device of a hybrid vehicle, size reduction and space saving are requested. On the other hand, in order to keep motor current small while avoiding a voltage increase of a battery, such a configuration is considered in that a battery voltage increased by a boost converter is supplied to an inverter driving a motor.
However, in consideration of a drive device of a hybrid vehicle including the integrated motor and inverter as well as an integrated boost converter, a reactor included in the boost converter is a relatively large component and thus may be a factor that hinders size reduction and space saving of the drive device.
An object of the present invention is to provide a drive device of a hybrid vehicle which is reduced in size and integrated with an inverter.